Elle wrote:
> On Sep 11, 8:41 pm, jim beam <m...@privacy.net> wrote:
>> here's something to consider - an old "trick of the trade" is to use
>> some of that crappy "stop oil consumption" additive when a dealer sells
>> a known dud car. it works fine for a while, then, once a few months
>> have gone by and it's no longer a quick come-back, it breaks down and
>> oil consumption rises again.
>
> I was not aware that such additives existed but I can certainly
> believe this is what happened and I got sold a car with a way worn
> engine. This may be a lesson of used car buying, even with a clean
> title and second owner status. Worst case I guess I may live with the
> oil consumption and then at some point chase down an engine to swap
> in.
>
> I will keep this thread updated.


There are two types of additives to lower oil consumption. One
swells the valve seals; if you did the seal replacement right then you
can rule that out. The other kind thickens the oil to slow blow-by past
the rings. That would have been removed not long after the oil change.
You can do a simple test to see if it's worn rings: pull all the plugs
and the air filter, then run a compression test with the throttle wide
open. If you have worn rings OR valves, the compression will be low.
Then squirt about a tablespoon of higher-weight oil like SAE 80 or 90
into each cylinder and repeat the test. If the compression shoots up,
you have worn rings. It if only rises slightly or not at all it's worn
valves.